Alan Inzer, 43, of Lake Charles, had chased the suspects, first in his car, then on foot before he was shot to death, officials said at an afternoon news conference.

Suspects were still at large Thursday afternoon and as many as 60 officers were searching the area where he was killed.

Lake Charles Police Chief Donald Dixon said Inzer was off-duty and driving his own vehicle with a friend around 1:30 a.m., when he noticed three to four men acting suspiciously in front of an abandoned building.

"Inzer pulled into the building's parking lot and the men ran toward Prien Lake Mall," said Sgt. Mark Kraus, a police spokesman.

Inzer pursued the men in his vehicle into a neighborhood and when the suspects split up, he stopped his car, got and followed at least one of them on foot.

Dixon said Inzer's friend got out as well and called 911 on his cell phone, when he heard a series of gun shots. When police arrived at the scene, they found Inzer dead, Kraus said.

"He was laying on his side next to a truck parked on the residential street. This is our worst nightmare," Dixon said. "We've lost one of our own."

Police later found a weapon which they believe was involved in the crime located three to four blocks northwest of the scene, Dixon said. He added that about 60 officers were on the case, pursuing various leads.

Dixon and Calcasieu Parish Sheriff Tony Mancuso urged witnesses to come forward with anything they heard or saw that could help solve the case.

"It hits home, and it hurts," Mancuso said of Inzer's death.

Inzer began working for the Sheriff's Office in 1989, where he served in a number of divisions.